I was imaging M51 last night and was struggling with the autofocus routine. It was ending up over a fairly large range for my setup (c9.25, .63 reducer, external focuser, ST2000XM). It never really would do a good v-curve and after stopping my sequence and working on the autofocus settings, I notice SGP would occasionally select the core of companion galaxy of M51 (NGC5195) and that would create a bad datapoint on the curve. This would happen a few times during the focus run. So the result would be sawtooth curve more or less. So I ended up disconnecting from SGP and using FocusMax via MaximDL on a nearby star.
I guess my question is how do I tweak the “nebula” slider bar to avoid SGP from using the galaxy core. I went from one end of the slide to the other and I could not get a reliable v-curve. I have followed the instructions on how to determine the step size and all that with my dial indicator. When galaxies and nebula do not cause problems, it works great. I kind of wish we could manually pick which stars in the FOV to base focus on as a override. Is that possible even? If it helps, I focus thru my Lum filter, 2x2, 5sec, dark frame enabled, 11 steps.
Thanks for any ideas/help.